I take it you forgot this thread I made not long after I joined:
https://www.lustria-online.com/thre...-star-trek-series-films-and-characters.19670/
However, for the purposes of this thread, I said DS9, because all of the characters have their good moments and the dark Dominion War story arc really stands out in this series.
Second I would say Enterprise - I've been rewatching it recently and seeing the transition from more 'ordinary' humans to the more disciplined, ethical and moral officers of the Federation is great, plus the Xindi arc, the Temporal Cold War and the Mirror Universe double episode all add some suspense and exciting new material.
Third would be Voyager - seeing all the new Delta Quadrant species (in particular Species 8472 - Star Trek Tyranids!), plus a mega conflict with the Borg and good characters like Neelix and the Doctor make this series enjoyable.
Fourth would be TNG. Though Patrick Stewart is excellent as Captain Picard and we get Q scenes aplenty, Wesley's know-it-all nerdiness and his mother's emotional crises ruin a lot of the series for me.
The Original Series is at the bottom of the rankings for the ones I've seen, because though it has some standout episodes ("Arena", "The Trouble with Tribbles" and "Mirror, Mirror" spring to mind), a lot of them are forgettable.
Discovery I never want to watch because it looks awful and they apparently killed off who promised to be a great captain (Jason Isaacs) in the first few episodes, replacing him with the far inferior Michelle Yeoh.
Picard I do want to see because of course it continues Captain Picard's story, though I'm concerned at the fan objection to it. Is it possible to explain why that's the case without spoiling it too much?